This invention relates to semiconductor devices and more particularly to the composition and process for eliminating corrosion within semiconductor packages.
Semiconductor devices, particularly semiconductor integrated circuits, are formed in a semiconductor chip or die, for example, of silicon, by standard photolithographic and diffusion techniques and then provided with suitable metallized bonding pads. The completed chip is placed in the suitable packaging structure having electric leads therethrough for providing electrical connection between interiors of the package and the circuit or system into which it is to be connected. The circuit between the chip and the package leads is completed by bonding wires. Typically, the bonding pads on the chip and the bonding wires are of aluminum. One prevalent problem with this type of package is that corrosion takes place between the aluminum bonding wire and the aluminum bonding pad thus resulting in early failure of otherwise operative semiconductor integrated circuit chips. This problem has been especially found in CMOS (complementary metal oxides semiconductor) integrated circuits packaged in dual-in-line ceramic packages. Although these packages are considered and intended to be hermetically sealed, it has been found that a certain amount of carbon dioxide and water is present in the packaged device. Hence, a mechanism for eliminating or gettering of this carbon dioxide and water vapor has been found to be necessary.